Detergent compositions containing hydrated alkali metal tripolyphosphates



June 25, 1968 FElERSTElN ET AL 3,390,093

DETERGENT COMPOSITIONS CONTAINING HYDRATED ALKALI METALTRIPOLYPHOSPHATES Filed June 1. 1965 3 Sheets-Sheet 1 'FRECURSOR SLURRYDEAERATOR HEATER MIXER REACTOR COOLER DRYER FIGURE 1 INVENTORS HAROLD E.FEIERSTEIN CHUNG Y. SHEN ROBE T R. VE EN ATJO RN E YQZ.

June 25, 1968 FE|ERSTE|N ET AL 3,390,093

DETERGENT COMPOSITIONS CONTAINING HYDRATED ALKALI METALTRIPOLYPHOSPHATES Filed June 1. 1965 3 Sheets-Sheet 2 FIGURE 2 INVENTORSHAROLD E. FEIERSTEIN CHUNG Y. SHEN June 25, 1968 DETERGENT COMPOSITIONSCONTAINING HYDRATED ALKALI Filed June 1, 1965 EXO ENDO

EXO

H. E. FEIERSTEIN ET AL 3,390,093

METAL TRIPOLYPHOSPHATES 3 Sheets-Sheet 5 FIGURE 3 I I I I 200 I00 I20I40 I60 80 2.00 L INVENTORS HAROLD E.FEIERSTEIN CHUNG Y. SHEN ROBERVERS/EN BY United States Patent 3,390,093 DETERGENT COMPOSITIONSCONTAIN- ENG HYDRATED ALKALI METAL TRI- POLYPHOSPHATES Harold E.Feierstein and Chung Yn Sheri, St. Louis, Mo.,

and Robert R. Versen, Belleville, Ill., assignors to Monsanto Company,St. Louis, Mo., a corporation of Delaware Continuation-impart ofapplication Ser. No. 200,325, June 6, 1962. This application June 1,1965, Ser. No. 460,205

39 Claims. (Cl. 252-138) This application is a continuation-in-part ofmy copending application Ser. No. 200,325, filed June 6, 1962, and nowabandoned.

This invention relates to novel methods for manufacturing detergentcompositions that contain hydrated alkali metal tripolyphosphates. Morespecifically, this invention relates to novel processes in which lowbulk density detergent compositions containing at least one hydratedalkali metal tripolyphosphate can be manufactured without beingspray-dried.

Heretofore, it was believed necessary that when a detergent manufacturerWanted to manufacture a detergent composition having a relatively lowbulk density (i.e., less than about 0.8), he had to utilize either verylight density raw materials or the process operation known asspray-drying in at least one stage of his overall detergentmanufacturing process. The spray-drying operation is, however, arelatively expensive one, requiring, first of all, a considerableinvestment of capital in the spraydrying equipment (including, forexample, such items as high pressure pumps, a very large spraying tower,and special facilities for heating, and controlling the flow of air forthe tower). In addition, the actual cost of the heat necessary for thespray-drying operations (to evaporate Water from detergent slurries) ishigh, as compared to the total cost of the raw materials in the final,relatively low bulk density detergent product. As a result of the highcost of spray-drying, many of the smaller detergent manufacturers havenot been able to afford to spray-dry their detergent products, and thushave been placed at a competitive disadvantage, because many consumersof detergent products prefer to use the lighter (lower bulk density)products.

The polyphosphate that is presently preferred for use in most detergentcompositions is a tripolyphosphate; particularly sodiumtripolyphosphate. Tripolyphosphates, however, have a decided shortcomingwhich can presently be overcome (in conventional detergent manufacturingpractice) as most only partially, and to that extent only by exercisingvery stringent precautions during the conven tional detergent processingsteps. This shortcoming is the result of the tripolyphosphatessusceptibility to hydrolytic degradation. Thus, during the time a slurryis being formulated, and ultimately spray-dried, a significantproportion of the tripolyphosphate is generally hydrolyzed toorthophosphates and pyrophosphates which are not nearly as effective (assequesterants) in building detergent products as is tripolyphosphate andgenerally, therefore, are not nearly as desirable as tripolyphosphate inthe final detergent products.

In addition, it is ordinarily preferred that before a detergent slurryis spray-dried, generally at least most of the sodium tripolyphosphatecontained therein be hydrated. However, when a slurry containinghydrated tripolyphosphate (derived by simply hydrating anhydrous sodiumtripolyphosphate) is spray-dried, a substantial proportion of thetripolyphosphate hydrate degrades (presumably because of the hightemperatures the slurry must be subjected to in order to be effectivelyspray-dried) to yield acidic decomposition products, which also are "icenot nearly as desirable in the final detergent products as is thetripolyphosphate hydrate.

Consequently, it is a primary object of the present invention to provideprocesses whereby detergent compositions that contain hydrated alkalimetal tripolyphosphates and have relatively low bulk densities can bemanufactured without the necessity of spray-drying.

It is another object of this invention to provide processes wherebydetergent compositions that have relatively low bulk densities and whichcontain hydrated alkali metal tripolyphosphates, particularly sodium.tripolyphosphate hexahydrate, can be manufactured without exposing thehydrated salts to excessively high degrading temperatures.

It is still another object of the present invention to provide processeswhereby detergent compositions having widely varying physical properties(including those having widely varying bulk density, particulatedsolids, and shaped solids that contain a cellular structure, as well asshaped solids that contain compressed particulated solids) can be madeutilizing practically the same basic processing equipment for each typeof compositions.

The above, as well as other objects of the invention which will becomeapparent from the following discussion, can be achieved in accordancewith this invention by utilizing selected process conditions and rawmaterials which will result in (a) the formation of a foam in adetergent slurry containing alkali metal trimetaphosphate, (b) thereaction of the trimetaphosphate with a strong base to thereby convertthe trimetaphosphate to tripolyphosphate, (c) the hydration of asubstantial proportion of the trimetaphosphate while the slurry is inthe foamed condition, and (d) removing sufficient water from the slurryWhile it is in the foamed condition to thereby form a solid (sometimesparticulated) porous product. In the present processes, generally (b)and (c) are performed simultaneously in view of the very fast rate ofhydration of the tripolyphosphate.

The processes for preparing light (low bulk) density detergentcompositions, in accordance with the present invention, require that aslurry be utilized in order to achieve several specific advantages,including mainly the achievement of a better uniformity of ingredientsthrough the final detergent products. Detergent slurries are wellknownin the art, and neednt be detailed here, except to point out that thosewhich can be used in the processes of this invention must contain atleast about enough water to hydrate all of the alkali metaltripolyphosphate in the final detergent compositions that can bemanufactured therefrom, and also at least enough water to initially lendfluid properties to the slurry. Thus, useful slurries generally shouldcontain at least about 10 weight percent of Water, based on the totalWeight of the completely formulated slurry. 'For some of the preferredembodiments of this invention, it is preferred that the slurries befluid and initially contain at least about 20 weight percent of water(and when sodium tripolyphosphate hexahydrate is to be formed in theseprocesses, at least about 5 Weight percent of water in excess of theamount required to pro duce said sodium tripolyphosphate hexahydrate).Because in most of the processes of this invention it will be necessaryto evaporate at least part of that water which is present in theslurries (especially that amount which is in excess of the amount thatcan be utilized to hydrate the polyphosphate salt), some of the benefitsthat can accrue to those who practice the invention will be mostapparent when slurries containing at most about 50 weight percent ofwater are utilized. Slurries differ from solutions in that the formercontain more than enough materials to dissolve in the continuous aqueousphase thereof, even though the materials dispersed through the aqueousphase may have a fairly high solubility in water.

It has been unexpectedly found that when the conversion of an alkalimetal trimetaphosphate (to tripolyphosphate) is made to occur during thetime in which one of the foregoing slurries is in a foamed condition, sothat sufiicient free water is removed from the slurry to result in athickening and ultimate setting up (solidification) of the slurry (byhydration of the tripolyphosphate often accompanied by the evaporationof some of the free water); solid, particulated and/or formed or moldedproducts having unexpectedly low bulk densities result therefrom. Theterm free water is herein intended to encompass that water which wasinitially in the slurry and which is present in the particularcomposition being referred to in an unbound (i.e., not present as thehydrate of any of the salts in the composition), unevaporated state. Itshould be noted that the use of the term free water with reference to agiven composition at any given time does not necessarily imply that thecomposition referred to is in a fluid or even a semi-fluid state, sincemany apparently solid detergent compositions can contain as much as tenweight percent or more of free water without losing substantially all oftheir solid properties.

It is an advantage of the present invention that practically anywater-soluble hydratable (that is, one that can be hydrated in anaqueous slurry) alkali metal tripolyphosphate salt that can be formedvia the interreaction of a strong base with an alkali metaltrimetaphosphate can be utilized in the manufacture of detergentcompositions in accordance with the present invention. Particularlypreferred, among this group (the hydratable alkali metaltripolyphosphates) are sodium tripolyphosphate (Na P O potassiumtripolyphosphate (K P O lithium tripolyphosphate (Li P O trisodiumdipotassium tripolyphosphate (N21 K P O and the like, while stillfurther preferred is sodium tripolyphosphate. Mainly because of theireconomic advantage over the other hydratable alkali metal polyphosphatesalts described above, as well as other considerations, generally thosepolyphosphate salts having sodium and/ or potassium cations are apreferred class for use in the processes of this invention.

The low bulk density detergent compositions that can be made via theprocesses of this invention are those that contain a significant amountof the hydrated alkali metal tripolyphosphate; that is, usually at leastabout 10 weight percent and often as much as about 75 weight percent,based on the total weight of the final solid detergent composition.However, gene-rally, it is preferred that the final compositions containbetween about and about 60 weight percent of the alkali metaltripolyphosphate salt, at least about 60 and preferably at least about75 weight percent of which is in the hydrated state.

Although it was pointed out in the objects, above, that in the processesof the present invention, the hydrated tripolyphosphate salts need notbe exposed to such high, degrading temperatures as those ordinarilyutilized in detergent spray-drying operations, it will neverthelessgenerally be necessary to apply heat in some manner to the detergentslurries that are utilized herein in order to attain slurry temperaturesof at least about 50 C. during some of the latter stages of the presentprocesses. One method which has been discovered whereby both heat andthe desirable tripolyphosphate can be introduced into the detergentprocesses of this invention simultaneously, and whereby severaladditional advantages can also be attained (including greater ease incontrolling the viscosity of the detergent slurries than is ordinarilypossible utilizing conventional slurry processes involving the use oftripolyphosphates and a faster overall detergent process as comparedwith conventional processes for manufacturing comparable detergentproducts, and others), is by utilizing as one of the major raw materialsin the detergent slurry an alkali metal trimetaphosphate, and preferablysodium trimetaphosphate. Consequently, such processes that involve theutilization of the heat of reaction of an alkali metal trimetaphosphatewith a strong base constitutes particularly preferred embodiments of theinvention. These preferred embodiments make it possible for a detergentmanufacturer to make advantageous use of the reaction of alkali metaltrimetaphosphates with a base in the presence of alkali metal cations(when a substantially completely water-soluble final detergentcomposition is desired) to produce an alkali metal tripolyphosphate. Thereaction, which is accompanied by the evolution of a large amount ofheat, is believed to be represented by the following series of steps:

Initially, the trimetaphosphate ring is cleaved by the base, forming thetripolyphosphate anion, as is shown in Equation 1:

slurry as the hydrate, as shown in Equation 2:

wherein M is an alkali metal cation and y is an integer which is equalto the number of water molecules that are necessary to make anidentifiable hydrated salt of the particular alkali metaltripolyphosphate that results from the above-described reaction.Generally, y will be a whole number Within the range of from 1 to 15.For the several reasons pointed out above, it is preferred that Mrepresent sodium and, therefore, that y equal 6. Note that initially thetrimetaphosphate could be either an acidic alkali metal trimetaphosphate(containing one or two acidic groups), a common alkali metaltrimetaphosphate (wherein all of its alkali metal cations are the same),or a mixed cation alkali metal trimetaphosphate (in which more than onetype of alkali metal cation is present therein). Thus, alkali metaltrimetaphosphates useful in the successful practice of the presentinvention are those that are watersoluble and that can be represented bythe formula wherein M is an alkali metal cation, A can be either H or analkali metal cation, and B can be either H or an alkali metal cation;and when A and/ or B are alkali metal cations, they can differ or bealike, and they do not necessarily have to be the same as M; although itis preferred that M, A and B be alkali metal cations and that they bethe same (and still further preferred that all of M, A and B aresodium). Typical non-limiting examples of the alkali metaltrimetaphosphates encompassed by the above formula include Na P O Na HPO 2 3 9, s a e 2 a 9 a a a a a s, LiH2P309, Rb3P309, CS3P309, Rb2HP309,Na2KP30g, NEIKzPaOg, Na LiP O Na2RbP30g, KzLiPgOg and tha like. Notethat when acidic trimetaphosphates are used in the practice of theprocesses of this invention, the amounts of strong base necessary toconvert the trimetaphosphate to the desired tripolyphosphate should beadjusted to take into account the necessity first to neutralize theacidic hydrogens on the acidic trimetaphosphate molecule.

When alkali metal trimetaphosphate, and particularly sodiumtrimetaphosphate, is utilized in formulating and manufacturing detergentcompositions according to the present invention, practically any amountof the material up to about 60 weight percent, based on the total weightof the fully formulated slurry, or even more, can be utilized. However,the amount of alkali metal trimetaphosphate that is actually utilizedusually depends upon basically two requirements of the detergentmanufacturer; the amount of tripolyphosphate which he desires in hisfinal detergent product, and the proportion of this amount oftripolyphosphate that should be in the hydrated state. Because theproducts which result from the practice of this invention shouldgenerally contain at least about weight percent of hydratedtripolyphosphate (when trimetaphosphate is used as a raw material), theslurries contemplated herein will ordinarily contain at least about 5 to8 weight percent initially (based on the weight of the slurry solids),of one of the alkali metal trimetaphosphates. On the other hand, becauseof the presence of water, strong base, and other detergent ingredientsin the fully formulated slurries, generally not more than about 60weight percent of any of the alkali metal trimetaphosphates can beutilized therein, if relatively complete conversion of thetrimetaphosphate to tripolyphosphate in the detergent manufacturingprocess is desired. It is preferred that the amount of alkali metaltrimetaphosphate which is utilized in the aqueous slurries in thepractice of this invention be from about 13 to about 60 percent byweight (based on the total weight of the fully formulated slurry justprior to the hydrating step of the processes of this invention, whichstep will be described in greater detail below).

For a more thorough understanding of the overall processes of thisinvention, reference is now made to FIG- URES l and 2 of the drawings.FIGURE 1 represents a schematic diagram of one of the preferredprocesses of the present invention, which preferred process isillustrated in more detail in FIGURE 2. The process illustrated in thesedrawings can be described as follows: Into a typical detergent crutcher1, fitted with an eflicient stirrer 3 and a jacket 5 through which steamor hot or cold water can be circulated by means of lines 7 and 8, arecharged (all parts being by weight) 355 parts of water, 782 parts ofsodium trimetaphosphate, 14 parts of sodium carboxymethyl-cellulose, 258parts of sodium dodecylbenzene sulfonate, and 191 parts of aqueoussodium silicate (47% solids) having an SiO /Na O ratio of 2.40, parts oflauryl monoisopropanolamide. The resulting precursor slurry is stirredfor about 15 minutes during which steam is passed through jacket 5 inorder to increase the temperature of the precursor slurry to about 85 C.The hot slurry is then pumped through lines 9 and 11 to a conven' tionalvacuum type deaerator 13. Deaerated slurry then passes through lines 15and 17, through slurry pump 19, and line 21 to an eflicient blender 31(in this instance line 21 leads to the inlet port of a conventionalcentrifugal pump). During its passage through line 21 the slurry ismonitored by means of a flow meter 25 and a density meter 27. While theprecursor slurry is being pumped through line 21, a 50 weight percentaqueous solution of sodium hydroxide is pumped from the caustic storagetank 33 through line 35 and caustic metering pump 37 to heat exchanger39 Where its temperature is increased to about 70 C. From there it ispumped through line 41 into the same entry port of blender 31 as thatinto which the precursor slurry is being introduced. The speed ofcaustic metering pump 37 is adjusted (depending upon the data from flowmeter 25 and density meter 27) so that for every 100 parts by weight ofprecursor slurry there are introduced into blender 31, 24.5 parts byweight of NaOH are introduced thereinto. This is approximately thestoichiometric amount of NaOH required to convert the sodiumtrimetaphosphate in the precursor slurry into sodium tripolyphosphate.Within less than a second, the NaOH is well blended with the precursorslurry .in blender 31 due to the extremely violent agitation of themixture achieved in the blender. The resulting final slurry is withdrawnfrom blender 31 through pipe 43 in which the final slurry remains foronly a few seconds. From pipe 43, the final slurry 49 is poured onto oneend of an endless stainless steel belt 45. At this point the slurry isstill fluid, and at a temperature of about C. Within the next severalseconds the temperature of the final slurry is observed to increase toabout 105 C. (due largely to the reaction of trimetaphosphate withNaOH), at which point the slurry appears to expand internally, forming alight density foam 47. Steam is observed escaping from the surface ofthe foam as it moves along belt 45. At the same time, the foam becomesgradually solidified into a hot granulated detergent mass 51. Thetemperature of the foamed material on belt 45 is maintained above aboutC. for several minutes after the foam has been converted into the,solidified detergent composition by means of a cover 53 over the belt aswell as by steam-heating the underside of the belt. After about 8minutes on belt 45, the granulated product 51 is gently wiped by aseries of rotating stainless steel wires 55 in order to break up anysoft agglomerated lumps, and then transferred via ramp 57 to transferbelt 59. From there it is dropped onto a vibrating screen 61 to break upany remaining agglomerates. At this point the detergent product containsabout 12 weight percent of free water and 13 weight percent of combined(hydration) water in the form of sodium tripolyphosphate hexahydrate.This product is then passed through a conventional fluidized bed dryer63 to remove almost all of the free water, and from there into productstorage bin 65.

The bases that can be utilized in the practice of this invention are allof those which can cause the formation of sufficient hydroxyl ions, inthe aqueous slurry, to react with the alkali metal trimetaphosphate,according to the foregoing suggested reaction. It has been found that ofthe group of materials known as bases, only the relatively strong onescan cause the reaction of trimetaphosphate to tripolyphosphate to occur.Thus, throughout the present specification and the appended claims, theterm strong base will be intended to encompass those bases that aresufficiently strong to cause the formation of excess hydroxyl ions inaqueous media that contain dissolved alkali metal tripolyphosphate. Forpurposes of this invention, the strong bases that can be utilized arethose that yield a solution pH measured at 25 C. of at least about 10.2when they are dissolved in distilled water at the 1 weight percentlevel. It will be understood that the term strong base encompasses, forexample, such basic compounds as for example, alkali metal carbonates,alkali metal silicates, tri-alkali metal orthophosphates, alkali metaland alkaline earth metal oxides, and the like (which compounds do notactually contain hydroxyl anions, but which cause hydroxyl ions [highpH] to result when they are dissolved in water), as well as some of theorganic quaternary ammonium hydroxides, the alkali metal hydroxides andthe alkaline earth metal hydroxides such as calcium hydroxide, andmagnesium hydroxide, etc. Economic considerations will generally dictatethat strong bases which are inorganic be used. Of these, it is preferredthat alkali metal hydroxides, carbonates, and silicates (having SiO /M Oratios lower than 2.0, where M is an alkali metal cation) be utilized.Still further preferred are the sodium and potassium forms of thesematerials.

The amounts of the various strong bases described above which can beutilized in this invention will vary considerably, depending upon suchfactors as the molecular weight of the base, its basic strength, rate ofdissolution in water, etc. The amount, however, will always besufficient to furnish enough hydroxyl ions so that at least asubstantial amount or proportion (i.e., at least about one-half andpreferably at least about seven-tenths) of the alkali metaltrimetaphosphate in the slurry can be converted into the correspondingalkali metal tripolyphosphate. Thus, the amount of the particularinorganic base that can be utilized (in the slurry) in the practice ofthis invention will generally be at least enough to furnish about oneand preferably at least about 1.4 mole equivalents of hydroxyl ions permole of trimetaphosphate which is present in the slurry. Because 2 molesof hydroxyl ions are necessary to convert one mole of trimetaphosphateto tripolyphosphate, it is still further preferred, when substantiallycomplete conversion of the alkali metal trimetaphosphate is desired,that the slurry be formulated to contain at least about '2 moles ofstrong base per mole of trimetaphosphate therein. Since very highconcentrations of base in the detergent slurries will sometimes causedegradation of tripolyphosphate (particularly hydratedtripolyphosphate), and also because when a very large excess of base isutilized some of the excess base (that in excess of the amount requiredto convert the trimetaphosphate) must ordinarily be neutralized withacid before the drying step of the process (i.e. in order to maintain adesirable alkalinity in the final detergent product), the amount ofstrong base present in the detergent slurries which areutilized in thepractice of the invention will generally not be more than about moles,and preferably at most about 6 moles of base per mole oftrimetaphosphate in the slurries. Additional precautions that shouldordinarily be observed when such extremely strong bases as the alkalimetal hydroxides, and particularly sodium hydroxides, are utilized forthe conversion of trimetaphosphate to tripolyphosphate will be discussedsubsequently, along with the discussion of the various manipulativeprocedures that can be utilized in the processes of this invention.

Although it is appreciated that some inorganic bases are conventionallyemployed in detergent compositions and processes, the amounts of basewith which this invention is concerned will practically invariably beover and above those amounts presently employed. For example, twopercent solutions of conventional spray-dried detergent composition indistilled water often exhibit alkaline pHs ranging from about 8 to about10.5 or perhaps even slightly higher than 10.5. These levels ofalkalinity are desired to be maintained in the final product because theproducts often perform better under slightly alkaline washingconditions. In addition, a certain degree of alkalinity is required inthe product in order to maintain the silicate corrosion inhibitors in awater-soluble state. The practice of the present invention, however,generally requires that significantly more base be incorporated into thedetergent slurries than was heretofore employed.

It is another advantage of the present invention that when alkali metaltrimetaphosphates are utilized as described heretofore, ready control ofthe rate of hydration of the resulting tripolyphosphate salt within thedetergent slurry can be obtained. This is a distinct advantage overdetergent slurry processes of the prior art wherein sodiumtripolyphosphate, for example, is the most widely used polyphosphatc rawmaterial, because the hydration rate of sodium tripolyphosphate isordinarily a very difficult but important process variable to control.This ready control of the rate of hydration lends an additionaladvantage of wide flexibility to the processes of the present invention.Some of the implications of this particular advantage will be discussedin greater detail below. Generally the higher the temperature of theaqueous mixture of strong base and alkali metal trimetaphosphate, thefaster is the rate of formation of the alkali metal tripolyphosphatethat results from the alkaline conversion of trimetaphosphate describedin Equation 1, above. However, so long as the strong base is withheldfrom slurries containing alkali metal trimetaphosphate, very little, ifany, conversion of the trimetnphosphate to tripolyphosphate occurs. nomattcr how high the temperature of the slurry is maintained.

The rate of conversion of trimetaphosphate to tripolyphosphate can beincreased by increasing the ionic strength (concentration) of a givendetergent slurry. Therefore, those who prefer to utilize very high ratesof conversion in the processes of this invention can advantageously doso by utilizing highly concentrated detergent slurries. It has also beendiscovered that the presence of more than about 0.5 weight percent ofsodium sulfate in the slurry (while the trimetaphosphate conversionreaction is being carried out) in some way acts as a catalyst for theconversion reaction, sometimes increasing the rate of conversion as muchas 50% or more.

Since a given amount of alkali metal trimetaphosphate in any givendetergent slurry contributes substantially less to the apparentviscosity of the slurry than would a corresponding amount of sodiumtripolyphosphate (which is generally largely present in the slurry asthe hexahydrate), for example, slurries having unexpectedly lowviscosities during the crutching stage of the detergent processes can bemade. This low slurry viscosity results in a considerable savings, ascompared to otherwise equivalent slurries containing hydrated orhydrating tripolyphosphatcs, in the total amount of power consumed inthe overall detergent processes, and particularly in the crutching stepof such processes. On the other hand, more concentrated slurries(containing less water) can be handled in a given piece of crutching orpumping equipment, if desired, as compared to equivalenttripolyphosphate hydrate-containing slurries. Data illustrated in Table1, below, give some idea of how great this reduction in slurry viscositycan be when sodium trimetaphosphate (plus about 2 moles of NaOH per moleof trirnetaphosphate) is utilized in the preparation of detergentslurries, as compared with a conventional procedure for preparing anequivalent detergent slurry utilizing sodium tripolyphosphate in theform of the low temperature modification.

TABLE I.-APPAREN[ SLUgEKE VISCOSITY MEASURED Slurry Viscosity inCentipoiscs 2 Time, Min.

'Irini etaphosphate Tripolyphosphate 415 400 H0 500 400 2, (300 4! ll,000 460 19, 000 19, 000

Ordinarily one need not be concerned over how hot the detergent slurriescontaining the alkali metal trimetaphosphates are maintained while thestrong base is essentially absent from the slurries. However, because ofthe extremely high rate of degradation of hydrated tripolyphosphatcs(such as the preferred sodium tripolyphosphate hexahydrate) in stronglybasic systems when the temperatures are raised substantially above aboutC., the temperatures of slurries formulated with alkali metaltrimetaphosphate that are utilized in accordance with this inventionshould generally be maintained below about C., and preferably belowabout l20 C. while the alkali metal trimetaphosphate is being convertedto tripolyphospnate. Similarly, since the rate of conversion oftrimetaphosphate to tripolyphosphate with a strong base increases withincreased slurry temperature, slurry temperatures above about 50 C., andpreferably above about 70 C., should generally be maintained during atleast the latter half of the conversion step. However, even lowertemperatures than about 50 C. can be utilized if desired. (Temperatureshigher than about 105 C. can be obtained in the slurries and reactionmixtures by carrying out the processes under pressures higher thanatmospheric.)

Even when fairly low slurry temperatures below about 70-89 C. areutilized during a large fraction or even most of the time during whichthe trimetaphosphate is being converted to tripolyphosphate, it isdistinctly advantageous to permit the temperature of the slurry to riseto the boiling point of the free water in the slurry during the latterstages of the conversion reaction so as to actually convert some of thewater in the slurry to steam. The steam, in turn then, usually beinggenerated initially in the form of discrete bubbles of gas (steam) inthe slurry can cause the conversion of the slurry into a fairly lightdensity foam. Then as the remainder of the trimetaphosphate is convertedinto tripolyphosphate (while the slurry is in the foamed state), and thetripolyphosphate in turn hydrates, the apparent viscosity of the slurrybecomes higher and higher until, after a substantial proportion of thefree water in the slurry has either been absorbed by thetripolyphosphate to form the hydrated salt, or has been evaporated outof the slurry, or both (generally both), the reaction mixture becomes asolid, seemingly, wet mass generally still containing several weightpercent of free water, which can be removed if desired by subsequentlydrying the wet mass, or by additional absorption of the free water viahydrate formation. Such delayed hydrate formation has been observed totake place even subsequent to the above-described conversion reaction.It can take place readily, for example, in compositions that containhydratable materials such as sodium sulfate, and certain of thephosphate salts that form their hydrates at temperature below those thatare generally utilized in the foaminghydration step (described above) ofthe processes of the present invention.

When the foregoing foaming-hydration step is performed under atmosphericpressure and detergent slurries having water alone as the continuousphase, it is usually necessary to heat the slurries to a temperaturebetween about 100 C. and about 105 C. in order to generate foam via theconversion of water to steam as described above. Sometimes, when it isdesirable to conduct the foaming-hydration step of these processes atlower temperatures than about 100105 C., a quantity of a relatively lowboiling, completely water-miscible organic solvent such as methanol,ethanol, isopropanol, acetone, dioxane, and the like, or combinations ofthese, can be utilized along with the water as the fluid continuousphase in the preparation of the detergent slurries described heretofore.

It will be noted that in either of these approaches the temperature ofthe reaction medium (the slurry which subsequently is converted into asolid detergent product during the foaming-hydration step) is maintainedsufficiently high to generate steam-in the form of pure water vapor oras the low boiling organic solvent/water azeotrope, for example,dependin upon the composition of the slurrys fluid continuous phasewhichsteam is the cause of the light density foam. It is not absolutelynecessary, however, that the gas which forms the foam is steam.Actually, particularly where lower slurry temperatures andtrimetaphosphate conversion rates are desired in the processes of thisinvention it is sometimes advantageous to create the foam, during thefoaming-hydration step described heretofore, by blowing, dispersion, orinjecting a gas other than steam into the slurry. This can be done byany of a number of ways which will become evident to those reasonablyskilled in the art from the present disclosure. The gas which isinjected can be 'air, oxygen, carbon dioxide, sulfur dioxide, nitrogen,nitrous oxide, hydrogen, propane, methane, ethane, argon, neon,superheated steam, hydrogen sulfide, and the like. It can also be any ofa number of relatively lower boiling synthetic materials which areeither gases at temperatu'es below about 100 C. and atmosphericpressure, or which can be converted readily into gases by makingrelatively minor adjustments in temperature and/or pressure, such as for10 example, the fluorinated hydrocarbons including CCl F, CCl F CClFCClF and the like. Generally, it is preferred that these gaseousmaterials be non-reactive with the other materials in the detergentcompositions at temperatures used during the practice of theseprocesses.

When conditions during the foaming-hydration step are such that the rateof hydration of the polyphosphate is relatively slow (such as whenslurry temperatures below about 70 C. are utilized during the conversionof one of the alkali metal trimetaphosphates) the reaction (hydrating)mixture must generally be maintained in the foamed state for a longerperiod of time. than when conditions are such as to encourage a higherrate of hydration, provided most of the benefits that can be attained bypracticing the present invention are desired. This amount of time can bereduced (other conditions remaining the same in any given process) byusing a procedure involving the injection of a gas, the gas being heatedprior to its introduction into the hydrating mixture to a temperaturehigh enough to result in the removal of some of the free water from theslurry via evaporation. Heat can also be applied directly to the slurryby means of a conventional heat exchanger or through the walls of thecrutcher pipe, belt, or other container in which the foaming-hydrationstep is being carried out.

Although several specific methods for the production of the requisitefoam in the detergent slurries have been outlined above, it will beevident from this disclosure that other procedures for generating thefoam can be utilized without necessarily detracting substantially fromthe bencfits that can result from practicing this invention. All this isordinarily necessary in this respect (in so far as the foaming-hydrationstep of these processes is concerned) for the practice of the presentinvention is that the slurry be foamed, and that at least a substantialpart of the hydration of the polyphosphate be performed while the slurryis in the foamed state. It is extremely difiicult, for example, toobtain final detergent products having very low bulk densities via theprocesses of the invention if the maintenance of the foam in the slurryand at least part of (preferably the latter part of) the hydration ofthe hydratable polyphosphates described above are not erformedsimultaneously. Generally, acceptable lower density detergent productscan be obtained when as little as about 5 weight percent (or even less)of the total hydratable tripolyphosphate in the composition of slurry ishydrated while the slurry is in the foamed condition, although it ispreferred that at least about 10 weight percent of the hydration occursduring this foaming-hydration step of the processes of the instantinvention.

It will be noted that the foam during the foaminghydration step can becontinually generated during the entire period, or during only a portionof the latter part of the period during which the polyphosphate ishydrated. Or suihcient foam can be generated initially, and the reactionconditions then adjusted and maintained so that at least a largeproportion of the bubbles of gas are maintained (held) in the slurryuntil it solidifies. Generally, the more (i.e., the greater the volumeof) bubbles that can be generated and held in the slurry during thefoaming-hydration step, the lighter or lower the bulk density of thefinal detergent product will be. Thus, for extremely low bulk densitydetergent products, generally the total volume of the foamed slurry (orthe light density foam) should be at least about percent, and preferablyat least about 200 percent (by volume) of the unaerated volume of theslurry, i.e., of the slurry volume, before it is transformed into thefoamed state.

It should be noted that in the foregoing discussion of thefoaming-hydration step of the processes of this invention, generally abetter foam, and consequently generally a more uniform final detergentproduct can be manufactured (particularly when the invention is utilizedas a continuous detergent process) when there is at least an effectiveamount of a foaming agent in the slurry at the time the slurry istransformed into the foamed condition. The term foaming agent isintended to include synthetic organic anionic, nonionic, and evenampholytic active detergent materials that are generally compatible withthe alkali metal polyphosphates in both solutions and slurries of theoverall detergent compositions. Thus the term foaming agent includes,for example, such individual organic detergent-active ingredients as thewell-known water-soluble soaps (i.e., the sodium and/or potassium saltsof coconut fatty acids, oleyl fatty acids, etc); water-soluble alkylarylsulfona-tes having from 6 to 20 carbon atoms, and preferably from 9 to17 carbon atoms, in their alkyl chain, such as sodium dodecyloenzenesulfonate and potassium tetradecylbenzene sulfonate; water-soluble alkylsulfates, Such as those that are manufactured by sulfating aliphaticalcohols having from 6 to 20 carbon atoms in their either branched orunbranched alkyl chains, including, typically, sodium and potassiumlauryl (C sulfate, sodium and potassium hexadecyl sulfate, sodium andpotassium octadecyl sulfate, etc.; as Well as alkali metal salts ofsulfated ethyles e oxide and/ or propylene oxide condensation productsmanufactured by ethoxylating and/or propoxylating (and subsequentlysulfating) various organic hydrophobic compounds containing activehydrogen such as alcohols, mercaptans, phenols, and amines; sodium andpotassium alkyl glyceryl ethers such as those derived from tallow andcoconut oil, including for example, sodium coconut oil fatty acidmonoglyceride sulfate, ctc.; fatty alkylolamides such asN-dodccylmonoethanolamide, N-octadecyl diethanolamide and the like;alcohol-alkylene oxide condensates (i.e., alcohols having from 8 to 20carbon atoms, in either straight or branched chain configuration, havingfrom about 6 to about 30 moles of ethylene oxide and/or propylene oxideper mole of alcohol in their molecules) alkylphenol-alkylene oxidecondensates (i.e., those made by condensing alkylphenol, having an alkylgroup that contains from about 6 to about 20 carbon atoms in the chainwith from about 6 to about 30 or more moles of ethylene oxide and/ orpropylene oxide per mole of alkylphenol); and the like. Of these, thosein the anionic class are preferred, while the fatty alkylol (or alcohol)sulfates having from 8 to 20 carbon atoms in their carbon chains arestill further preferred for use in the processes of this invention.Sometimes when the nonionic detergent active materials are utilized inthe absence of a significant amount of one of the anionic detergentactive materials in the manufacture of detergent products in accordancewith this invention, an unexpectedly high slurry viscosity develops atone stage of the crutching operation. It has been found that thisproblem can be alleviated by adding the hydratable rripolyphosphate lastor nearly last, and very slowly (i.e., over a period of 2 minutes ormore) with agitation into the other detergent ingredients.

The term foaming agent also includes materials which, when added to theslurry, contribute to some extent to the tenacity or the toughness orstability of the bubbles in the foamed slurry. Such materials (otherthan the well-recognized detergent-active ingredients such as thosedescribed above) include polymers that are watersoiuble to an extentsufiiciei'zt to contribute to the stability of the foam such as sodiumcarboxyrnethylcel-lulose; sodium hydroxyethyl cellulose,polyvinylpyrollidone; hydrolyzed and partially hydrolyzed polymers madeby reacting a lower alkylene such as ethylene, propylene, and methylvinyl ether with maleic and/or fumaric anhydride, for example,ethylenc-maieic anhydride, propylene fumaric anhydride, methyl vinyiether-maleic anhydridc; polyvinyl alcohol; and the like.

The amount of foaming agent in the slurries during the foaming-hydrationstep of this invention can be varied considerably. Generally, more thanabout 0.1 weight percent, based on the wei ht of the completelyformulated slurry, should be utilized when final detergent productshaving fairly low bulk densities are desired. However, for very low bulkdensities in the final detergent products made via these processes,usually at least about 0.25 and preferably at least about 0.5 weightpercent of the foaming agent should be used. Since different foamingagents perform with different degrees of efiiciency, depending upon manyfactors including slurry temperature, slurry solids concentration, theactual ingredients contained in the slurry, and many others, optimumconcentration for each foaming agent cannot be set out herein withdefinity. However, it is believed Within the ability of those reasonablyskilled in the art, in view of this disclosure, to ascertain the optimumconcentrations for the manufacture of their oWn particular detergentproduct.

Practically any manipulative procedure can be utilized in the practiceof the present invention in order to accompiish the various steps orstages in the processes set out above. For example, the order ofaddition of the various ingredients in the preparation of any of theslurries, except those that contain more than a few weight percent ofalkali metal trimetaphosphate, is not at all critical. Normally the onlyprecaution one needs to observe in order to obtain excellent results isthat compositions which contain tripolyphosphate should generally not beblended with the strongest bases such as sodium hydroxide unless thebase is diluted to below about 50 weight percent, and preferably belowabout 35 weight percent, with water before the strong base is blendedwith the alkali metal trimetaphosphate. Otherwise, the strong baseshould be effectively diluted by the Water in the slurry itself asquickly as possible after the base is added to the slurry. However, if amanufacturer is not particularly concerned about completely minimizingthe degradation of the tripolyphosphate during his manufacturingoperations, even this precaution need not be strictly observed. Whenthis precaution is observed, one advantageous method for doing so whichcombines several of the unexpectedly desirable attributes from usingalkali metal trimetaphosphate, and especially sodium trimetaphosphate,is to first prepare a practically completely formulated detergentslurry; which usually contains any foaming agent, antiredepositionagent, optical brighteners, bleaches, fabric softeners, alkali metalsilicate or fiuosilicate corrosion inhibitors, or whatever othermaterials that are desired in the final detergent composition orproduct, but which does not contain the strong base (called herein theprecursor slurry). The precursor slurry, then should also contain thetrimetaphosphate. Because of the unexpectedly low viscosity of slurriesthat contain the trimetaphosphate, precursor slurries havingcomparatively little water .(as compared to conventional detergentslurries that practically invariably contain hydrating or hydratedtripolyphosphate), but which retain their pumpability and other fluidcharacteristics, can be made. For example, precursor slurries containingas much as weight percent of non-volatile material (solidsincluding thetrimetaphosphate) can be manufactured and utilized in the processes ofthis invention. So long as the strong base is withheld from theprecursor slurry, its low viscosity can generally be maintained almostindefinitely, with substantially no degradation of the trirnetaphosphateoccurring. Thus a detergent manufacturer can prepare his precursorslurries well in advance of the time he wants to produce his finaldetergent product if he desires. In addition, if part of his processingequipment breaks down, a detergent manufacturer can hold his precursorslurry for long periods of time if need be, practically with impunity,whereas, if he had prepared conventional slurry using sodiumtripolyphosphate, hydrolytic degradation of the tripolyphosphate in theslurry upon prolonged storage could practically destroy the utility ofthe slurry for his processes.

Having prepared his precursor slurry, the detergent manufacturer can nowutilize several approaches to the final essential step in the processesof this invention. Since l 3 it is desirable that the foaming-hydrationstep be performed relatively quickly, and because the rate of conversionof the trimetaphosphate to tripolyphosphate is very high at elevatedtemperatures, the precursor slurry can be heated to a temperature aboveabout 50 C., and preferably above about 70 C., in one of the preferredembodiments of this invention before the strong base is intermixedtherewith. In that case, the conversion reaction proceeds quickly(usually within about 2 minutes when an alkali metal hydroxide such assodium hydroxide or potassium hydroxide is utilized, for example, at thehigher precursor slurry temperatures), after the strong base is blendedinto or with the precursor slurry. As a matter of fact, the heat ofconversion of the trimetaphosphate to tripolyphosphate, and thence tohydrated tripolyphosphate is generally sufficiently high that theconversion reaction can become essentially autocatalytic in nature ifmost of this heat is not deliberately removed from the slurry. Forexample, when a precursor slurry containing more than about weightpercent of sodium trimetaphosphate and having a temperature of about 80C. is quickly intermixed with about 2 moles of sodium hydroxide per moleof trimetaphosphate under practically adiabatic conditions, theconversion reaction commences immediately. The heat from the conversioncauses an increase in the temperature of the reaction mass, which inturn causes an increase in the rate of conversion of thetrimetaphosphate to tripolyphosphate. Increases of tenfold or more inthis rate of conversion can be accomplished by raising the temperatureof the reaction mass about 25 C.

Thus, by intermixing the strong base with the precursor slurry at arelatively high temperature, the manufacturer can be reasonably assuredthat his foaming-hydration step will not require an excessively longtime. Actually, provided the heat is not removed from the system, steamand foam can usually be generated in detergent slurries which aretreated like that described immediately above (precursor slurry strongbase) within a few minutes of the time the strong base is intermixedwith the hot precursor slurry. Practically equivalent results can alsobe obtained by intenmixing the precursor slurry and strong base, or evenby formulating the slurry in any particular manner desired, at a fairlylow temperature (i.e., below about 50 C.) and subsequently raising thetemperature of the slurry to above about 70 C., for example, by means ofexternally applied heat. This can be accomplished by passing the slurrythrough or over an electric or steam heated exchanger.

Another method by which a manufacturer can accomplish this same resultis by passing the fairly cool, completely formulated slurry (containingboth trimetaphosphate and strong base) through a steam-traced pipe,using higher than atmospheric pressures and temperatures above about 105C. if desired to obtain still higher conversion rates. Before theconversion has been completed it is generally preferred that the slurrybe deposited into or onto some container in order for theabove-described foaming-hydration step to be completed in the absence ofan excessive amount of agitation. (Excessive agitation during the stageof these processes wherein the setting up of the detergent slurriesoccurs can result in a considerable increase in the bulk density of thefinal detergent product, as compared to that of one that has not beensubstantially agitated during the latter portion of thefoaming-hydration step.) Thus, when the foaming-hydration step isperformed in a vessel containing a paddle or stirring blade or othermeans for internally agitating the slurry, it is best that the agitatingmeans be stopped while the foamed slurry solidifies. Or, if desired, theslurry can be dumped into a pan or other container, or onto a movablebelt from the internally agitated vessel shortly before the foamedslurry solidifies in order to minimize the agitation during this settingup period. The strong base should be'thoroughly and evenly distributedthrough the slurry before the solidification stage is reached, however.

Still another convenient method for manufacturing low bulk densitydetergents via the precursor slurry procedure described above is to doso continuously. For example, the hot precursor slurry can be meteredinto a conventional mixing device in which the precursor slurry can bethoroughly and quickly intermixed with the strong base, which is alsometered into the device at a rate calculated to yield the desired finalproduct. Then the completely formulated slurry can be poured or droppedor pumped from the mixing device onto or into a container and therepermitted to either begin or continue to foam and subsequently solidifyinto the final detergent product. This method is described hereinbeforeand is illustrated in FIGURES l and 2. Cold precursor slurry can bemetered through an electric or steam-traced pipe or series of pipesprior to its being inserted into the mixing device. When such aprocedure is utilized continuously, it is convenient and advantageous topour the completely formulated slurry onto a movable belt that isdesigned to hold fluid substances. The slurry can then foam and steam onthe belt, and subsequently solidify thereon. Then the lighter densityproduct can be passed through a drying oven usually operated at atemperature which. does not excessively degrade the hydratedtripolyphosphate) when it is desired to remove some of the excess freewater that may be present. This drying oven step is not essential forthe successful practice of the invention, however. Or the hot,completely formulated slurry can be held in a pipe or conduit or othercontainer under higher than atmospheric pressure, if desired, until thetemperature of the slurry reaches the boiling point of the watertherein. Then it can be sprayed or dribbled into a high tower similar toa conventional spray-drying tower and dropped through the tower. Thetower can contain warm, dry air to aid in the removal of some of thefree water, but the temperature in the tower should generally be heldconsiderably lower than those that are utilized in conventionalspray-drying operations. Thus, foaming, hydration and solidificationduring the drop through the Warm tower can result in the formation of alow bulk density detergent product via a completely different .mechanismthen is conventionally employed in similar equipment (i.e., aspray-drying tower).

Since the addition of heat into a chemical process is expensive, it isgenerally desirable to develop and utilize means for carrying out thechemical process with as little consumption of added heat as possible.Consequently, one of the particularly prefer-red embodiments of thepresent invention involves the efiicient utilization of heat resultingfrom (a) the reaction of the trimetaphosphate with the strong base, and(b) the hydration of the resulting tripolyphosphate. in thisparticularly preferred embodiment, the heat evolved during thesechemical processes is utilized to both (a) raise the temperature of theslurry to that at which the steam is formed and (b) to cause theevaporation of some of the free water from the resulting particulated,light density product. Thus, it is preferred that the interreaction ofthe trimetaphosphate and the strong base be carried out in such a waythat the reaction is essentially adiabatic, in which practically none ofthe heat resulting from the exothermic reaction is allowed to escapefrom the slurry, so that the tempera ture of the slurry is increased bythe internal addition of such heat of reaction into it. In order toproperly utilize this approach in the practice of the present processcs,it is necessary, however, that the initial temperature of the finalslurry (containing both trimetaphosphate and strong base, as Well as anyother desired detergent ingredients) be at least a certain minimumlevel, the actual value of which certain minimum temperature beingdetermined by several factors including, for example (a) the totalamount of trimetaphosphate that is to be reacted with the strong base(generally the larger this amount the lower the initial temperatureneeds to be), (b) the type of tripolyphosphate hydrate to be made (theheats of hydration differ), (c) the proportions and kinds of otheringredients in the slurries (this effect is relatively minor, however)and (d) the final reaction temperature expected (i.e., the temperatureof the slurry during the foaminghydration step). In processes involvingthe manufacture of detergent compositions containing sodiumtripolyphosphate hexahydrate, in which processes trisodiumtrimetaphosphate is reacted with a strong sodium cation-containing basesuch as sodium hydroxide, for example, it was pointed out hereinbeforethat the use of at least about 15 Weight percent of sodiumtrimetaphosphate in slurries constitute preferred levels of practice inthe present processes. When 15 weight percent of sodium trimetaphosphateis reacted with a stoichiometric amount of NaOH in a typical detergentslurry containing at least about 50 weight percent of total solids (atmost about 50 weight percent of water), the initial temperature of theslurry (immediately after the trimetaphosphate and the sodium hydroxideare intermixed) must be at least about 80 C. (in order for the heats ofreaction described above to carry the temperature of the slurry to about105 C., which is about its boiling point under 1 atmosphere ofpressure). But when as much as 50 weight percent of sodiumtrimetaphosphate (in the final slurry) is to be converted to sodiumtripolyphosphate hexahydrate via reaction with NaOH, the initialtemperature of the slurry normally need only be about 60 C. Tabulatedbelow are ranges of the various essential elements that must be observedin order to practice successfully this particularly preferred embodimentof the present invention.

Element Range Percent water in slurry 20-50 Percent sodiumtrimetaphosphate 1560 Percent NaOH 4-16 Temperature 2 45-90 In terms ofpercent by Weight of the slurry immediately prior to the beginning ofthe reaction of NaOH with trimetaphosphate.

Just after the sodium trimetaphosphate and the NaOH have been intermixed(immediately prior to the beginning of their interreaction) Thisparticularly preferred embodiment of the present invention isillustrated in Example I, below. It should be understood that whenrelatively lower amounts (within the above range) of sodiumtrimetaphosphate are to be converted in these processes, relativelyhigher initial slurry temperatures must be used, and when relativelylarger amounts of trimetaphosphates are to be converted, relativelylower temperatures can be used.

In the following examples, which are illustrative of some of theembodiments of the present invention, all parts are by weight unlessotherwise specified.

EXAMPLE I Into a conventional stainless steel mixing vessel which isfitted with a conventional paddle-type stirrer and jacketed so thateither hot or cold water or steam can be used in the jacket, are charged2,000 parts of water, 900 parts of sodium dodecylbenzene sulfonate, 600parts of sodium lauryl sulfate, 1,000 parts of sodium sulfate, 2,840parts of sodium trimetaphosphate, 1,140 parts of sodium silicate (47%solids) having an SiO /Na O ratio of 2.40 and 55 parts of detergentgrade sodium carboxymethylcellulose. The resulting precursor slurry isstirred for about minutes, during which time the temperature of theslurry is raised to 80 C. by circulating steam through the mixer jacket.

Into the hot precursor slurry which is being moderately agitated is thenquickly poured 1,590 parts of a 50% aqueous sodium hydroxide solution.After about 45 seconds of moderate agitation, during which the sodiumhydroxide is blended well with the precursor slurry, the temperature ofthe slurry beings to rise. The agitation is halted just before thetemperature of the slurry reaches C. When the slurry temperature reachesabout 103 C., the slurry begins to expand in volume, rising in themixing vessel, so that the volume of the foamed slurry is at least about2-8 times that of the precursor slurry. Steam begins to escape from thebubbling mass, and it hardens quickly, to a particulated, seemingly wet,soft mass. Within a few minutes, no more steam is evolved from thesolidified reaction mass, and its volume decreases slightly while .it iscooled to room temperature. At this point it contains about 30 weightpercent of water of which about 12.7% is considered free water and about92% of the theoretical equivalent (based on the amount of sodiumtrimetaphosphate charged into the precursor slurry) of sodiumtripolyphosphate, which is substantially all present in the form of thehexahydrate. After being air-dried overnight to remove most of theexcess free water, the final detergent product is free flowing,noncaking, essentially non-hygroscopic, has a bulk density of about0.35, and contains about 54 weight percent of sodium tripolyphosphatehexahydrate.

Note that in Example I, no dilficulty whatever is experienced withrespect to lumps in either the precursor or the completely formulatedslurries. Had the same slurry preparation procedure been followedutilizing anhydrous sodium tripolyphosphate instead of sodiumtrimetaphosphate, many troublesome lumps of undissolved, partiallyhydrated tripolyphosphate would probably have formed, especially if thehigh temperature modification had been utilized, which lumps aregenerally not desired by detergent manufacturers in either theirslurries or in their final detergent products.

Another surprising result which can be obtained by practicing theprocesses of this invention is that final detergent products that aremanufactured via a procedure such as that shown in Example I, above,yield substantially clear aqueous solutions, even when they aredissolved in water to the extent of about 0.5 to 1.0 weight percent. Bycomparison, conventional heat-dried (generally spraydried) detergentproducts practically invariably yield turbid aqueous solutions. Data inTable 2 aptly illustrate this advantage:

TABLE 2.CLARITY OF 0.5% AQUEOUS DETERGENT SOLUTIONS Detergent: 1 Percenttransmittance 2 Invention product 100 Conventional-detergent A(spray-dried) 37.5 Conventional-detergent B (spray-dried) 10.0

1 Invention product, made in Example I, but formulated to substantiallymatch conventional detergent B. I

2 Percent transmitted light through a l-inch cell containing 0.5 Weightpercent detergent solutions, as compared with distilled water.

Conventional-detergent B and the Invention Product used as a basis forthe data in Table 2 contained about 20 weight percent of a mixture ofsodium dodecylbenzene sulfonate and lauryl isopropanolamide, plus about50 weight percent of sodium tripolyphosphate, about 5 Weight percent ofsodium silicate solids, about 23 weight percent of sodium sulfate, and atotal of about 2.5 weight percent of minor adjuvants.Conventional-detergent A is a well-known nonionic detergent. While thedata in Table 2 is illustrative of only a few specific detergents,practically all conventional spray-dried detergents yield relativelyopaque solutions similar to those of detergents A and B in Table 2,while those made via the present processes are considerably more clearin every instance (when similar formulations are compared and nowaterinsoluble materials are utilized in the formulations).

EXAMPLE II A precursor slurry similar to that prepared in Example I isformulated, except that 3,100 parts of a physical blend containing about50 Weight percent of sodium trimetaphosphate and 50 weight percent ofanhydrous 1 7 high temperature crystalline modification sodiumtripolyphosphate are utilized in place of the sodium trimetaphosphate.

After the temperature of the precursor is raised to about 90 0, 1,160parts of a 35 weight percent aqueous solution of sodium hydroxide isquickly (within about 30 seconds) blended into the precursor slurry.Then the mixing is stopped, and the slurry permitted to foam. As soon asthe volume of the foamed slurry is about times that of the precursorslurry, the foamed slurry is poured from the mixing vessel in a layerabout 4 inches deep and about 2 feet wide on a moving belt. The reactionmixture on the belt quickly solidified into a soft, particulated masswhich, after passing through a tumbling rotary dryer in which dry air at100 C. is passed over counter-currently against the showering solids inabout 10 minutes, is an excellent free flowing, non-caking, particulateddetergent product which can readily be packaged and sold directly to theconsuming public. Its bulk density is about 0.45.

EXAMPLE III A precursor slurry is prepared which is similar to that madeaccording to Example I, above. Its temperature is about 45 C. It is thencontinuously metered into a stain-' less steel conduit having an insidediameter of about 1 inch. The conduit is traced for a distance of about30 feet with a pressurized steam jacket to heat the precursor slurry toa temperature near boiling. The heated precursor slurry is joined by a50 weight percent aqueous solution of sodium hydroxide metered into amixing nozzle at a rate proportional to 2.01 moles of NaOH per mole ofsodium trimetaphosphate in the precursor slurry. The mixing nozzle isequipped with an agitator and several baffles spaced and designed toachieve quick and intimate mixing of the precursor slurry with thestrong base. The temperature of the resulting completely formulatedslurry is raised to about 115 C. by the heat of reaction and thepressure is increased to above about p.s.i.g. From the open end of themixing nozzle the slurry is discharged onto a moving belt, where steamis quickly generated and the product foams, and solidified into a soft,spongy material. After being air cooled the final detergent product hasa bulk density of about 0.65. The cooled spongy material can be easilydisintegrated into a free flowing granular product or properly sized forlaundry detergents.

The processes of the present invention can be advantageous in detergentmanufacture in many ways, some of which have been mentioned heretofore.Additionally, however, it is a very valuable advantage thatmanufacturers can now utilize a hydratable polyphosphate (thetrimetaphosphate) in only one physical form for the manufacture of avariety of forms and types of products. For example, the finalrelatively low bulk density detergent products can be passed through acompressing machine and then ground to produce a product having a higherbulk density if desired. Control of the density of the final detergentproducts can also be obtained by utilizing a small amount of aconventional anti-foam agent in the slurry during the foaming-hydrationstep. Generally, the more antifoam agent (such as the well-knownsilicones, for example) the higher will be the bulk density of the finaldetergent product. In addition, by simply changing the types andquantities of ingredients in the precursor and/or completely formulatedslurries, described above, a detergent product having practically anydesired final formula (provided it also contains a substantial amount ofone of the desired hydrated tripolyphosphates) can be manufactured viathe processes of this invention. Manufacturers of tableted or formeddetergents can also utilize this invention to advantage. For example,some conventional detergent tablets physically deteriorate when they areexposed to a highly humid atmosphere for more than a few hours,apparently because they initially contain anhydrous sodiumtripolyphosphate which tends to swell in volume when it is hydrated tothe hexahydrate upon contact with the humid atmosphere. By comparison,tablets prepared from a final detergent product such as that prepared inExample I, above, remain physically stable for weeks or more even thoughthey are exposed to high humidity and relatively high temperatures.

EXAMPLE IV A part of the soft, spongy, particulated product of ExampleIII is taken from the moving belt (before it is cooled and air dried)and in addition introduced into a conventional soap milling machine(often called a plodder). In the milling machine, the temperature of thedetergent is maintained at about 100 C. The detergent is milled verybriefly (because it is already homogeneous) and then extruded onconventional equipment into bar form at a temperature of from about 50C. to about 100 C. preferably from about 50 C. to about C. After theyare cooled to about 25 C., the resulting detergent bars are uniform,homogeneous and excellent detergent laundry bars. Detergent bars andtablets can also be produced by simply compressing in suitableconventional molding equipment any of the porous, particulated productsresulting from processes such as are illustrated in FIGURE 2 and Example1, above, under pressures of from about 200 to about 4000 pounds persquare inch.

It is still another advantage of the present invention that it can beutilized to manufacture relatively low bulk density formed soliddetergent products that contain a network of air spaces or cells. Thiscellular structure, combined with the overall formed shape (such as inthe form of a bar of soap or practically any other desired shape) canresult from a closely controlled release of steam during thefoaming-hydration step of the processes of this invention. Essentially,in order to manufacture such solid, cellular, formed products, the totalamount of steam that is formed should be controlled so that very little,if any of the steam bubbles out of the foamed slurry. Thus, ordinarilyin the manufacture of one of these formed solid compositions, thereaction rate, and/ or concentration of the alkali metaltrimetaphosphate and other hydratable poly-phosphate materials in theslurry should be controlled or regulated so that the total amount ofsteam and/or other gas that is generated in the slurry is not more thanabout four times the total unaerated volume of the completely formulatedslurry (i.e., the foamed slurry volume is preferably less than about 5times its unaerated volume). When one of the more efiicient foamingagents is present in the slurry, the volume of the foamed slurry can beincreased to about 8 or even 10 times the unaerated volume of the slurrywithout an excessive breaking of the steam or gas bubbles within thefoam before it solidifies (which breaking and excessive evolution ofsteam or gas from the slurry at or near the time the slurry solidifiedcan result in the particulation of the final detergent product, which isgenerally not desired in the manufacture of formed solid products havingcellular internal structures).

Perhaps the best way to accomplish the above-described control of thetotal amount of gas formed in the slurry is to handle the slurry in sucha way that the desired volume of gas is all that is formed therein, andsuch gas is formed only during the latter portion of thefoaming-hydration step. For example, when slurries containing betweenabout 10 and about 60 weight percent of sodium trimetaphosphate areutilized in these processes at least about half of the sodiumtrimetaphosphate should be converted to tripolyphosphate without theformation in the slurry of a substantial proportion of gas or steam.Then, during the foaming-hydration step, only enough gas should beinjected into or generated in the slurry to increase the volume of thefoamed slurry as indicated above. It can be understood from the abovethat since the evolution of large quantities of gas from the foamedslurry in this particular aspect of the invention is not desired, thegreater proportion of the free water initially in the slurries should beremoved or tied up via hydration of the tripolyphosphate, and otherhydratable materials in the composition such as sodium sulfate, sodiumsilicate and the like. Generally, it is preferred that at least about 50weight percent of the free water be bound as the hydrate of thetripolyphosphate. This limitation on the amount of gas generated in theslurry can be accomplished, for example, by intermixing the strong baseand trimetaphosphate at a fairly low temperature, so that a large partof the heat from the conversion of trimetaphosphate to tripolyphosphatecan be consumed in raising the temperature of the slurry to the boilingpoint of the water contained therein, or to that point at which someother gas is generated therein. Some of the heat can also be removedfrom the slurry by means of appropriately placed heat exchangers.

Another procedure that can be efiectively utilized for the manufactureof formed low bulk density solid detergent products is one that involvesthe passage of a completely formulated slurry through a hot conduit,under pressure if necessary in order to prevent the evolution of steamthrough most of the tripolyphosphate hydration period. Then, when thereremains only a fraction of the hydration to be completed, which fractionis sufiicient to cause the formation of about the desired amount of foamin the slurry, the slurry is poured into a mold or container. At thispoint, the temperature is generally at or above the temperature abovewhich gas is formed in the slurry. The continued hydration (andconversion when the trimetaphosphate reaction is utilized) causes thegeneration of gas in the slurry, and also the final solidification ofthe slurry into the desired cellular product. When conditions areutilized in these processes such that no gas is generated in the slurry,the correct proportion of gas can be injected into the slurry shortlyprior to the time it solidifies in any particular desired manner, asoutlined above.

It can be readily appreciated from the foregoing that practically anymaterials that can be used in conventional processes for manufacturingdetergent compositions can be used in the processes of the presentinvention. It is also significant that the invention need not be limitedto being practiced with slurries that contain all of the ingredientsusually found in conventional heat-dried detergent compositions. Whenalkali metal carbonate is used as the strong base in some of theprocesses of this invention, the resulting final products can containseveral percent of alkali metal bicarbonate in addition to the hydratedpolyphospfiate salt. And when excess alkali metal carbonate is utilized,it can appear in the final detergent product either as the carbonate oras its hydrate, depending upon the particular process conditions thatare utilized. In addition, the processes described herein can beutilized for the manufacture of practically pure low bulk density sodiumtripolyphosphate hexahydrate, as well as many mixed bydratedpolyphosphate compositions that in turn can be utilized as raw materialsin conventional processes for manufacturing detergent products.

Detergent products that are manufactured via the preferred processes ofthe present invention (i.e., via reaction of a sodium trimetaphosphatewith a strong base containing sodium cations, such as sodium hydroxide)can be specifically identified as such due to the surprising fact thatthe crystalline sodium tripolyphosphate hexahydrate contained thereinyields peculiar (but specific and reproducible) results when tested viaconventional difierential thermal analysis (D.T.A.) techniques. Thus,while crystals of sodium tripolyphosphate hexahydrate (STP-6H O) indetergents made conventionally (via hydration of anhydrous sodiumtripolyphosphate) yield D.T.A. curves like that of FIGURE 3 (of thedrawings), crystals of STP-6H O in detergent compositions made via theprocesses of the present invention surprisingly yield D.T.A. curves likethat of FIGURE 4 (of the drawings).

One can immediately differentiate between these two types of crystals byapplying conventional D.T.A. techniques to STP-6H O crystals that havebeen separated (by conventional techniques) from the other materials inthe original detergent formulation. Note that while the STP'6H Oresulting from the present processes (FIG- URE 4) remains initiallystable up to a temperature of about 120 C., that resulting fromconventional detergent processes (FIGURE 3) never approaches 120 C., andactually loses all of its water of hydration before a temperaturesignificantly above about 110 C. is approached. The reason or reasonsfor this amazing stability (of the STP'6H O crystals in the detergentsmade via the processes of the present invention) to initial thermaldegradation is not known. However, lack of an explanation of why thispeculiar thermal stability exists does not prevent its proper use as amethod for identifying detergent products made via the presentprocesses. Thus, if the detergent does not contain particles that havebeen spray-dried, if it does not contain flakes (such as would bepresent in drum-dried products), and if the STP-6H O crystals containedtherein exhibit initial D.T.A. thermal degradation at a temperaturebetween about 115 C. and about 125 C., it is a detergent composition ofthe present invention. In the differential thermal analysis of STP-6H Oduring the preparation of the curves shown in FIGURES 3 and 4, 0.05 gramof the material to be tested were introduced into 4 mm. glass tubes andheated under nitrogen at a rate of 4 C. per minute, starting at 20 C.

What is claimed is:

1. A process which comprises forming an aqueous slurry containing (a) atleast about 8% by weight of a water-soluble alkali metaltrimetaphosphate salt, (b) an amount, sufiicient to convert a majorproportion of said trimetaphosphate salt to a tripolyphosphate, of abase of a strength such that a 1% by weight solution of the base indistilled water provides a pH of at least about 10.2 at C., (c) anamount of water at least 5% in excess of that required to hydrate saidtripolyphosphate and equal to at least about 10% by weight but not morethan by weight of said slurry; interspersing a gas in said slurry toform a foam; said gas being selected from the group consisting of watervapor and gases which are non-reactive with the other materials in saidslurry at temperatures of from about 50 C. to 135 C.; and maintainingthe temperature of said foam within the range of from about 50 C. toabout 135 C. while removing sufficient free water from said foam to forma porous solid product containing a substantial proportion of hydratedtripolyphosphate.

2. A process as in claim 1, wherein said foam is maintained at atemperature between about 50 C. and about 12 C. while removingsufiicient free water from said foam to form said porous solid product.

3. A process as in claim 1, wherein said alkali metal trimetaphosphateis sodium trimetaphosphate and said alkali metal tripolyphosphate issodium tripolyphosphate hexahydrate.

4. A process as in claim 1, wherein said slurry also contains at leastabout 0.1 weight percent of a foaming agent selected from the groupconsisting of water soluble organic detergent active materials andwater-soluble organic polymer materials.

5. A process as in claim 4, wherein said foaming agent is a watersoluble organic anionic surface active agent which is compatible withsaid alkali metal tripolyphosphate.

6. A process as in claim 5, wherein said surface active agent is a fattyalcohol sulfate containing from about 6 to about 22 carbon atoms.

7. A process as in claim 3, wherein the amount of water initially insaid slurry is at least about 20 weight percent, based on the totalweight of said slurry.

8. A process as in claim 1, wherein said strong base is selected fromthe group consisting of alkali metal hydroxides, alkali metalcarbonates, and alkali metal silicates having Si /M O ratios, wherein Mis an alkali metal cation, below about 2.

9. A process which comprises forming an aqueous slurry by intermixingwith water at least about 10 weight percent, based on the weight of thetotal solids of said slurry, of trisodium trimetaphosphate;interspersing a gas into at least a portion of said slurry to therebyform a light density foam, said gas being selected from the groupconsisting of water vapor and gases which are non-reactive with theother materials in said slurry at temperatures of from about 50 C. to135 C.; intermixing into said slurry an amount of a strong base selectedfrom the group consisting of sodium hydroxide, sodium carbonate, andsodium silicates having SiO /Na O ratios below about 2; reacting asubstantial proportion of said trisodium trimetaphosphate with saidstrong base to thereby produce sodium tripolyphosphate hexahydrate; andremoving sufiicient free water from said foam to result in theproduction of a solid, porous composition containing said sodiumtripolyphosphate hexahydrate; the amount of water in said slurry inexcess of that amount required to produce said sodium tripolyphosphatehexahydrate being such that the heat generated by the exothermicreaction of said trisodium trimetaphosphate with said strong base issufiicient to result in the evaporation from said foam of sufficientwater to convert said foam into said solid, porous product.

10. A process which comprises the steps of (a) rapidly mixing into astream of a precursor slurry a metered quantity of an aqueous basicsolution said precursor slurry being at a temperature of from 50 C. to135 C. and containing at least about 8% by weight of a Watersolublealkali metal trimetaphosphate salt, an amount of water such thatsubsequent to the addition of said basic solution the slurry containsfrom about 10% by weight to about 50% by weight of water, and at leastabout 0.1% by weight of a foaming agent selected from the groupconsisting of water-soluble organic detergent active materials andwater-soluble organic polymer materials, and said basic solution beingof a concentration such that said metered quantity thereof contains anamount of base sufficient to convert a major portion of saidtrimetaphosphate salt to a tripolyphosphate and such that said slurrysubsequent to the addition of said basic solution contains an amount ofwater at least in excess of that required to hydrate saidtripolyphosphate, said base being of such strength that a 1% by weightsolution thereof in distilled water provides a pH of at least about 10.2at 25 C.; (b) transferring said stream containing said basic solutiononto a moving surface such that it is in a substantially unconfinedstate free to expand in volume due to the formation of foam and suchthat it loses moisture by evaporation; and (c) maintaining said foam ata temperature above about 80 C. but below about 135 C. on said movingsurface until it has lost sufficient free water to form a porous solidproduct.

11. A process as in claim 10, wherein said slurry initially contains atleast about weight percent of said sodium trimetaphosphate and at leastabout 0.5 weight percent of sodium sulfate.

12. A process as in claim 10, wherein said base is selected from thegroup consisting of alkali metal hydroxides, alkali metal carbonates andalkali metal silicates having SiO /M O ratios (where M is an alkalimetal cation) below about 2.

13. A process as in claim 12, wherein said alkali metal trimetaphosphateis sodium trimetaphosphate.

14. A process as in claim 13, wherein said slurry initially containsfrom about 13% by weight to about 60% by weight of said sodiumtrimetaphosphate, said foaming agent is selected from the groupconsisting of anionic and nonionic detergent active materials and ispresent in said slurry in an amount equal to at least about 0.5% byweight of said slurry, the stream of said slurry to which said basicsolution is added is at a temperature of from about 50 C. to about 120C., said slurry, subsequent to the addition of said basic solution,contains at least 20% by Weight of water, and said metered quantity ofsaid basic solution contains a quantity of base at leaststoichiometrically equivalent to the sodium trimetaphosphate present insaid slurry but not more than six times that required to react with saidsodium trimetaphosphate.

15. A process as in claim 14, wherein said strong base is sodiumhydroxide.

16. A process as in claim 14, wherein said strong base is potassiumhydroxide.

17. A process which comprises intermixing water and sodiumtrimetaphosphate to thereby form a fluid dispersion having a continuousaqueous phase and a dispersed phase containing sodium trimetaphosphate,the total amount of said sodium trimetaphosphate in said dispersionbeing between about 8 and about weight percent; adjusting thetemperature of at least a portion of said dispersion to between about 60C. and about 120 C.; intermixing into said portion an aqueous solutioncontaining at least about 1.4 moles of sodium hydroxide per mole of saidtrimetaphosphate in said portion to thereby form a blend; allowing theheat of conversion of said sodium trimetaphosphate to sodiumtripolyphosphate to vaporize a substantial proportion of the Water insaid blend at a temperature but above about 50 C. below about 135 C.whereby said portion is formed into a light density foam; andsimultaneously evaporating some of said water and hydrating said sodiumtripolyphosphate, whereby sufiicient free water is removed from saidportion to result in the formation of a solid, particulated compositioncontaining sodium tripolyphosphate hexahydrate.

18. A process as in claim 17, wherein the temperature of said portion ismaintained below about 120 C. subsequent to the addition of said sodiumhydroxide.

19. A process as in claim 17, wherein said blend additionally containsan effective amount of a water-soluble foaming agent selected from thegroup consisting of water-soluble organic detergent active materials andwater-soluble organic polymer materials.

20. A process as in claim 19, wherein said foaming agent is present insaid blend in an amount equal to at least about 0.1 weight percent,based on the total weight of said blend.

21. A process as in claim 19, wherein said foaming agent is awater-soluble organic detergent which is compati'ble with sodiumtripolyphosphate.

22. A process as in claim 21, wherein said organic detergent is awater-soluble anionic organic detergent.

23. A process as in claim 22, wherein said anionic organic detergent isa water-soluble alkylbenzene sulfonate.

24. A process as in claim 22, wherein said anionic organic detergent isan alkylol sulfate containing from 8 to 20 carbon atoms in its alkylchain.

25. A process as in claim 24, wherein the concentration of said alkylolsulfate in said blend is at least about 0.5 weight percent, based on thetotal weight of said blend.

26. A process as in claim 25, wherein said blend additionally containsbetween about 1 and about 30 weight percent of an alkylbenzene sulfonatehaving from 12 to 26 carbon atoms in its molecule.

27. A process which comprises intermixing water, so-

dium trimetaphosphate, and a foaming agent to thereby form an aqueousslurry containing between about 10 and about 60 weight percent of saidsodium trimetaphosphate and at least about 0.5 weight percent of saidfoaming agent, said foaming agent being selected from the groupconsisting of water-soluble organic detergent active materials andWater-soluble organic polymer materials; adjusting the temperature of atleast a portion of said slurry to between about 70 C. and about C.;intermixing into said portion an aqueous solution containing at mostabout 50 weight percent, based on the weight of said solution, of sodiumhydroxide, and containing therein from about 2 to about moles of saidsodium hydroxide per mole of said trimetaphosphate in said portion tothereby form a blend; and thereafter maintaining the temperature of saidblend below about 120 C. and at the boiling point of the water in saidblend until a substantial proportion of said water is converted intosteam, whereby a light density foam is formed in said portion andsufficient water is removed from said foam to result in the formation ofa solid, porous composition containing sodium tripoly-phosphatehexahydrate.

28. A process which comprises forming a slurry initially containing fromabout 20 to about 50 weight percent of water, from about to about 60weight percent of trisodium trirnetaphosphate, from about 4 to about 16weight percent of sodium hydroxide, and at least about 0.5 weightpercent of a water-soluble anionic organic detergent; adjusting thetemperature of at least a portion of said slurry to from about 45 toabout 90 C.; permitting the temperature of said portion to increase tothe boiling point of the water in said portion as a result of theexothermic reaction of said sodium hydroxide with said sodiumtrimetaphosphate; maintaining the temperature of said portion at aboutsaid boiling point until a substantial proportion of the Water in saidportion is converted into steam, whereby said portion is initiallyconverted into a light density foamed slurry and sulficient water isremoved from said foamed slurry to thereby convert said foamed slurryinto a solid, porous composi- 1 tion containing from about 20 to about93 weight percent of sodium tripolyphosphate hexahydrate.

29. A process as in claim 28, wherein said slurry also contains at leastabout 0.5 weight percent of sodium sulfate.

30. A process for manufacturing a formed solid com position containinghydrated alkali metal tri-polyphosph-ate and a multitude of gas-filledcells, which process comprises the steps of (a) intermixing sodiumtrimetaphosphate, water, and a strong base selected from the groupconsisting of alkali metal hydroxides, alkali metal carbonates, andalkali metal silicates having SiO /M O ratios (where M is an alkalimetal cation) below about 2, to thereby form a fluid slurry containingfrom about 10 to about 60 weight percent of said sodiumtrimetaphosphate, at least about 10 weight percent of water and anamount of said strong base, equal to at least about the stoichiometricamount required to convert said trimetaphosphate to tripolyphosphate;

(b) reacting together at least about .half of said trimetaphosphate andsaid base without the formation in said slurry of a substantialproportion of foam;

(c) thereafter generating gas in said slurry at a temperature aboveabout 50 C. but below about 135 C. to thereby form a foamed slurry, saidgas being selected from the group consisting of water vapor and gaseswhich are non-reactive with the other materials in said slurry attemperatures of from about 50 C. to 135 C., and the total volume of saidfoamed slurry being at most about 10 times the unaerated volume of saidslurry; and

( d) removing a quantity of free water from said foamed slurry, saidquantity being sutficient to result in the formation of said solidcomposition and at least about 50 Weight percent of said quantity beingreacted with said tripolyphosphate to form said hydrated alkali metaltripolyphosphate.

31. A process as in claim 30, wherein said alkali metal is sodium.

32. A process as in claim 31, wherein said base is sodium hydroxide.

33. A process as in claim 32, wherein step (c) is performed at atemperature below about 120 C.

34. A process as in claim 32, wherein the total volume of said foamedslurry is between about 1.5 and about 5 times said unaerated volume.

35. A process for manufacturing a detergent bar composition, whichprocess comprises the steps of (a) intermixing Water, a water-solubleorganic detergent active material, and a material which reacts withwater at a temperature below about 135 C. to produce a water-solublealkali metal polyphosphate hydrate to thereby form a fluid slurry;

(b) incorporating a gas into at least a. portion of said dispersion tothereby form a light density foam, said gas being selected from thegroup consisting of water vapor and gases which are non-reactive withthe other materials in said slurry at temperatures of from about 50 C.to 135 C., and allowing at least a substantial proportion of saidmaterial to react with at least a portion of said water to form saidpolyphosphate hydrate while said portion of said dispersion is in afoamed condition and at a temperature of from about 50 C. to about 135C.;

(c) removing sufficient free Water from the continuous aqueous phase ofsaid foam while said material is being reacted with said water tothereby form a solid, particulated, porous product containing hydratedalkali metal polyphosphate and said water-soluble organic detergentactive material; and

(d) compressing, extruding and cutting said product to thereby form saiddetergent bar composition.

36. A tableted composition manufactured in accordance with the processof claim 35.

37. A solid, particulated detergent composition manufactured inaccordance with the process of claim 28.

38. A detergent composition containing a Water-soluble organic detergentactive material from about 10 to about weight percent of sodiumtripolyphosphate hexahydrate crystals, said crystals exhibiting aninitial dehydration point, by differential thermal analyses, betweenabout C. and about C.

39. A detergent bar composition manufactured in accordance with theprocess of claim 35.

References Cited UNITED STATES PATENTS 3,000,831 9/1961 Tuvell 2521383,133,024 5/1964 Feierstein et al. 252138 2,557,132 6/1951 Mochel 23-1072,811,419 10/1957 Hartlapp et al. 23107 2,365,190 12/1944 Hatch 2522,622,068 12/1952 HiZer 252138 2,897,155 7/1959 McNaught et al. 2521092,947,701 8/1960 Ruff 252109 3,303,134 2/1967 Shen et al. 252135 LEON D.ROSDOL, Primary Examiner.

ALBERT T. MEYERS, SAMUEL H. BLECH,

Examiners. I. GLUCK, Assistant Examiner.

1. A PROCESS WHICH COMPRISES FORMING AN AQUEOUS SLURRY CONTAINING (A) ATLEAST ABOUT 8% BY WEIGHT OF A WATERSOLUBLE ALKALI METAL TRIMETAPHOSPHATESALT, (B) AN AMOUNT SUFFICIENT TO CONVERT A MAJOR PROPORTION OF SAIDTRIMETAPHOSPHATE SALT TO A TRIPOLYPHOSPHATE, OF A BASE OF A STRENGTHSUCH THAT A 1% BY WEIGHT SOLUTION OF THE BASE IN DISTILLED WATERPROVIDES A PH OF AT LEAST AOBUT 10.2 AT 25* C., (C) AN AMOUNT OF WATERAT LEAST 5% IN EXCESS OF THAT REQUIRED TO HYDRATE SAID TRIPOLYPHOSPHATEAND EQUAL TO AT LEAST ABOUT 10% BY WEIGHTD BUT NOT MORE THAN 50% BYWEIGHT OF SAID SLURRY; INTERSPERSINGA GAS IN SAID SLURRY TO FORMA FOAM;SAID GAS BEING SELECTED FROM THE GROUP CONSISTING OF WATER VAPOR ANDGASES WHICH ARE NON-REACTIVE WITH THE OTHER MATERIALS IN SAID SLURRY ATTEMPERATURES OF FROM ABOUT 50*C. TO 135*C.; AND MAINTAINING THETEMPERATURES OF SAID FOAM WITHIN THE RANGE OF FROM ABOUT 50*C. TO ABOUT135*C. WHILE REMOVING SUFFICIENT FREE WATER FROM SAID FOAM TO FORM APOROUS SOLID PRODUCT CONTAINING A SUBSTANTIAL PROPORTION OF HYDRATEDTRIPOLYPHOSPHATE.
 10. A PROCESS WHICH COMPRISES THE STEPS OF (A) RAPIDLYMIXING INTO A STREAM OF A PRECURSOR SLURRY A METERED QUANTITY OF ANAQUEOUS BASIC SOLTION SAID PRECURSOR SLURRY BEING AT A TEMPERATURE OFFROM 50*C. TO 135*C. AND CONTAINING AT LEAST ABOUT 8% BY WEIGHT OF AWATER-SOLUBLE ALKALI METAL TRIMETAPHOSPHATE SALT, AN AMOUNT OF WATERSUCH THAT SUBSEQUENT TO THE ADDITION OF SAID BASIC SOLUTION THE SLURRYCONTAINS FROM ABOUT 10% BY WEIGHT BO ABOUT 50% BY WEIGHT OF WATER, ANDAT LEAST ABOUT 0.1% BY WEIGHT OF A FOAMING AENT SELECTED FROM THE GROUPCONSISTING OF WATER-SOLUBLE ORGANIC DETERGENT ACTIVE MATERIALS ANDWATER-SOLUBLE ORGANIC POLYMDR MATERIALS AND SAID BASIC SOLUTION BEING OFA CONCENTRATION SUCH THAT SAID METERED QUANTITY THEREOF CONTAINS ANAMOUNT OF BASE SUFFICIENT TO CONVERT A MAJOR PORTION OF SAIDTRIMETAPHOSPHATE SALT TO A TRIPOLYPHOSPHATE AND SUCH THAT SAID SLURRYSUBSEQUENT TO THE ADDITON OF SAID BASIC SOLUTION CONTAINS AN AMOUNT OFWATER AT LEAST 5% IN EXCESS OF THAT REQUIRED TO HYDRATE SAIDTRIPOLYPHOSPHATE, SAID BASE BEING OF SUCH STRENGTH THAT A 1% BY WEIGHTSOLUTION THEREOF IN DISTILLED WATER PROVIDES A PH OF AT LEAST ABOUT 10.2AT 25*C.; (B) TRANSFERRING SAID STREAM CONTAINING SAID BASIC SOLUTIONONTO A MOVING SURFACE SUCH THAT IT IS IN A SUBSTANTIALLY UNCONFINEDSTATE FREE TO EXPAND IN VOLUME DUE TO THE FORMATION OF FOAM AND SUCHTHAT IT LOSES MOISTURE BY EVAPORATION; AND (C) MAINTAINING SAID FOAM ATA TEMPERATURE ABOVE ABOUT 80*C. BUT BELOW 135*C. ON SAID MOVING SURFACEUNTIL IT HAS LOST SUFFICIENT FREE WATER TO FORM A POROUS SOLID PRODUCT.